About AudioLab
AudioLab is a free, browser-based suite of audio analysis tools built for music producers, sound engineers, podcasters, DJs, and anyone who works with audio. Every measurement runs entirely inside your browser — no files are ever uploaded to a server.
Our Tools
Audio Analyzer
Drop any audio file to measure BPM, integrated LUFS (ITU-R BS.1770-4), musical key, peak dBFS, clipping, dynamic range, sample rate, and channel count. Includes a full waveform seekbar, real-time frequency spectrum, and oscilloscope.
Microphone Test
Test any microphone or audio interface in your browser. Displays a real-time VU meter with peak hold, detects your device name and sample rate, and runs a pass/fail checklist covering signal presence, clipping, and sample rate.
Tone Generator
Generate pure sine, square, sawtooth, or triangle waves from 20 Hz to 20 kHz. Eight preset test tones for speaker frequency response testing, hearing range checks, acoustic treatment verification, and audio equipment troubleshooting.
Platform Standards
After analyzing a track, AudioLab compares your integrated LUFS against the loudness targets for YouTube (−14 LUFS), Spotify (−14 LUFS), Apple Music (−16 LUFS), Podcast standard (−16 LUFS), and EBU R128 broadcast (−23 LUFS).
Why Browser-Based?
Running audio analysis in the browser means your audio never leaves your device. There is no upload step, no waiting for a server, no size limits, and no account required. The Web Audio API gives us direct access to high-performance audio processing that runs as fast as native software on modern hardware.
This also means AudioLab works offline — once you've loaded the page, you can analyze audio without an internet connection.
Who Is This For?
- Music producers & mixing engineers — Check LUFS before mastering, detect BPM for tempo-matching samples, verify peak and clipping.
- Podcasters & broadcasters — Confirm your episode meets the −16 LUFS podcast standard or EBU R128 before publishing.
- DJs & live performers — Quick BPM and key detection for tracks in your library, tone generator for PA testing at soundcheck.
- Audio students & educators — Visualize waveforms and frequency spectra for classroom demonstrations and learning exercises.
- Streamers & content creators — Test microphone signal before going live, confirm loudness levels match platform requirements.
Technical Approach
AudioLab uses the Web Audio API for all signal processing. BPM is detected via spectral flux analysis on the sub-140 Hz kick band. LUFS is computed with a full two-stage K-weighting IIR filter (ITU-R BS.1770-4) with gated integration. Key detection uses a chromagram built from a hand-rolled radix-2 FFT, correlated against Krumhansl–Schmuckler major and minor profiles.
The spectrum analyzer renders a log-scaled FFT with gradient fill updated at 60 fps via requestAnimationFrame. The oscilloscope renders time-domain waveform data from a 2048-sample ring buffer.
Contact
For feedback, bug reports, or questions, please reach out via email at contact@rswaver.com or open an issue on GitHub.